The present invention relates to a method of detecting an unknown signal and estimating a source location of the unknown signal using aircraft provided with an automatic dependent surveillance-broadcast (ADS-B) system, and more particularly, to a method of rapidly detecting an unknown signal posing a threat to an air traffic control (ATC) from aircraft provided with an ADS-B system, and estimating a source location of the unknown signal based on the detected unknown signal.
A global navigation satellite system (GNSS) is a system for precisely tracking a location of a ground target on land or an air target using a global navigation satellite network. The GNSS includes a plurality of global navigation satellites, a receiver to receive a signal transmitted from the plurality of global navigation satellites, a ground surveillance station, and a system maintainability surveillance system. A method applied to the GNSS may be implemented by a receiver receiving signals transmitted from navigation satellites and determining a location of the receiver based on measured distances from navigation satellites. For example, use of the GNSS is widespread throughout fields of aerospace, shipping, and automotive navigation systems due to various advantages. Such benefits may be characterized by a signal being obtainable through the receiver irrespective of a geographical location of a user, the receiver being a minimal-size, and mobile positioning being available through an output obtained in real time.
Amid increased global flight demands as of late, an air traffic controller workload has also been on the rise, leading to issues in terms of security, speediness, and efficiency. Due to a limited air traffic management (ATM) system being operated on land only, development of an automatic dependent surveillance-broadcast (ADS-B) system designed to provide complementary air-to-surface and air-to-air functions is garnering attention.
The ADS-B system is a mutually cooperative surveillance system sharing information on locations or speeds of aircraft between controllers and pilots. The international civil aviation organization (ICAO) recommends that an aircraft be equipped with the ADS-B system which is acknowledged to be an appropriate and inexpensive universal system having a novel configuration for a communications, navigation, surveillance/air traffic management (CNS/ATM) system.
In the ADS-B system a single vast wireless network as shown in FIGS. 1 through 5, included are an air traffic control (ATC) serving as a wireless access point and an aircraft serving as a client. Here, the aircraft reports a location of the aircraft through the network, receives traffic situations and other information from a ground system, and issues a timely warning, as necessary, to a controller by providing information integrated by a computer of the ground system. A global navigation satellite illustrated in an upper portion of FIG. 1 connects communication amongst ground systems.
The ADS-B system gathers location information of aircraft by employing the GNSS capable of superior precision positioning than a radar technology generally used, and transmits the location information to the ground system to be used for the ATC. However, in an occurrence of disturbance or interference of a GNSS signal caused by an unknown signal or a purposeful unknown signal, flight security of the aircraft may be jeopardized. In particular, when a high power unknown signal is operated, multiple aircraft may be affected simultaneously and flight security may be placed in peril due to a vast region influenced by the unknown signal and thus, causing an issue to the ATC.
In a presence of such an unknown signal, an occurrence of an unknown signal, and a source location of the unknown signal may be estimated using a signal received from receivers disposed on ground. However, more often than not, the unknown signal is not properly detected because a portion of the receivers on the ground is not affected by the unknown signal, resulting in difficulty in detecting the occurrence of the unknown signal and the source location of the unknown signal. Moreover, when an unknown signal received by a ground receiver is distorted by refraction or reflection, and analyzed to estimate a source location of the unknown signal, precise estimation may not be achieved.
An aspect of the present invention provides a method of detecting an unknown signal and estimating a source location of the unknown signal which is conceived to resolve an issue of detecting an unknown signal and estimating a source location of the unknown signal using the unknown signal received by a ground receiver in a conventional technology. The method according to the present invention aims at efficient reception of an unknown signal, relatively rapid and precise detection of a presence of an unknown signal by analyzing an undistorted unknown signal, and estimation of a source location of the unknown signal.